检索结果-内蒙古大学图书馆

arXiv 2023年

作者： Guo, Gabe Goldfeder, Judah Lan, Ling Ray, Aniv Yang, Albert Hanming Chen, Boyuan Billinge, Simon J.L. Lipson, Hod Columbia University Department of Computer Science New YorkNY10027 United States Columbia University Department of Applied Physics and Applied Mathematics New YorkNY10027 United States Duke University Department of Mechanical Engineering and Materials Science DurhamNC27708 United States Columbia University Department of Mechanical Engineering New YorkNY10027 United States

The revolution in materials in the past century was built on a knowledge of the atomic arrangements and the structure-property relationship. The sine qua non for obtaining quantitative structural information is single crystal crystallography. However, increasingly we need to solve structures in cases where the information content in our input signal is significantly degraded, for example, due to orientational averaging of grains, finite size effects due to nanostructure, and mixed signals due to sample heterogeneity. Understanding the structure property relationships in such situations is, if anything, more important and insightful, yet we do not have robust approaches for accomplishing it. In principle, machine learning (ML) and deep learning (DL) are promising approaches since they augment information in the degraded input signal with prior knowledge learned from large databases of already known structures. Here we present a novel ML approach, a variational query-based multi-branch deep neural network that has the promise to be a robust but general tool to address this problem end-to-end. We demonstrate the approach on computed powder x-ray diffraction (PXRD), along with partial chemical composition information, as input. We choose as a structural representation a modified electron density we call the Cartesian mapped electron density (CMED), that straightforwardly allows our ML model to learn material structures across different chemistries, symmetries and crystal systems. When evaluated on theoretically simulated data for the cubic and trigonal crystal systems, the system achieves up to 93.4% average similarity with the ground truth on unseen materials, both with known and partially-known chemical composition information, showing great promise for successful structure solution even from degraded and incomplete input data. The approach doesn’t presuppose a crystalline structure and the approach are readily extended to other situations such as nanomaterials and te

关键词： Carrier concentration

来源：评论

学校读者我要写书评

暂无评论

The Application of the Coupled Acoustic-Structural Approach (Casa) Method on the Free Vibration of Submerged Structures

SSRN

引用

SSRN 2023年

作者： Liu, Zhenhui Ullestad, Oskar Engineering Consultancy Department of New Energy Aker Solutions AS Trondheim7435 Norway Department of Mechanical and Marine Engineering Western Norway University of Applied Sciences Haugesund5528 Norway Department of Physics and Technology University of Bergen Bergen5007 Norway

Traditionally, the consideration of the surrounding water during the modal analysis of submerged structures has been done by applying constant added mass factors. This method may lose its accuracy for complicated structures, especially those with bends and multi-plane topology. The present study utilizes the coupled acoustic structural approach (CASA) to obtain natural frequencies on submerged structures. The work compares the simulated CASA results with experimental results. Four experiments with objects with different geometry were chosen;a straight pipe, cantilever plates, stiffened cylindrical shell, and a disk. We found that the CASA method produced accurate results for the three first eigenmodes compared to the experimental results. It could simulate bending, twisting, ovality, and stretching mode shapes with an accuracy of less than 10% difference. Additionally, we applied the CASA method to two submerged jumper structures for the first time. We found that the CASA method gives accurate modal analysis results and is recommended to be used. © 2023, The Authors. All rights reserved.

关键词： Modal analysis

来源：评论

学校读者我要写书评

暂无评论

Calibration free, time-resolved diffuse optical spectroscopy using combined monte-carlo and diffusion theory 11

Calibration free, time-resolved diffuse optical spectroscopy...

引用

Biomedical Applications of Light Scattering XI 2021

作者： Helton, Michael McMaster, Carter Mycek, Mary-Ann Vishwanath, Karthik Applied Physics Program University of Michigan Ann Arbor United States Department of Physics Miami University OxfordOH45056 United States Biomedical Engineering Department University of Michigan Ann Arbor United States

ISBN: (数字)9781510641501

ISBN: (纸本)9781510641495

Near-infrared spectroscopy has been widely employed in biophotonics to study and quantify the optical properties of biological tissues. Unlike steady-state approaches, time-resolved spectroscopic techniques enable optical absorption and scattering properties of the medium to be separated, allowing for quantitation of depth-dependent absolute tissue optical properties. However, robust analysis of time-resolved signals requires careful consideration of calibration techniques and computational models. Here, we consider the effect of the time window employed when fitting a diffusion theory model to Monte-Carlo simulations. Next, we describe the impact of the temporal position of the instrument response function (IRF) in recovery of the optical properties. Finally, we discuss a technique to analyze time-resolved measurements without knowledge of the timescale of the IRF or the time-resolved measurement byfitting the relative shape of the photons' distribution time-of-flight (DTOF). © 2021 SPIE. All rights reserved.

关键词： Near infrared spectroscopy

来源：评论

学校读者我要写书评

暂无评论

Constructing Pd-N interactions in Pd/g-C_(3)N_(4)to improve the charge dynamics for efficient photocatalytic hydrogen evolution

引用

Nano Research 2022年第4期15卷 2928-2934页

作者： Xudong Xiao Siying Lin Liping Zhang Huiyuan Meng Jing Zhou Qi Li Jianan Liu Panzhe Qiao Baojiang Jiang Honggang Fu Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People’s Republic of ChinaSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China School of Safety Engineering Heilongjiang University of Science and TechnologyHarbin 150080China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Chinese Acad Sci Shanghai Synchrotron Radiat FacilShanghai Adv Res InstShanghai 201204China

The formation of chemical bonds between metal ions and their supports is an effective strategy to achieve good catalytic ***,both the synthesis of active metal species on a support and control of their coordination environment are still ***,we show the use of an organic compound to produce tubular carbon nitride(TCN)as a support for Pd nanoparticles(NPs),creating a composite material(NP-Pd-TCN).It was found that Pd ions preferentially bind with the electron-rich N atoms of TCN,leading to strong metal-support interactions that benefit charge transfer from g-C_(3)N_(4)to Pd.X-ray absorption spectroscopy further revealed that the metal-support interactions resulted in the formation of Pd-N bonds,which are responsible for the improvement in the charge dynamics as evidenced by the results from various techniques including photoluminescence(PL)spectroscopy,photocurrent measurements,and electrochemical impedance spectroscopy(EIS).Owing to the good dynamical properties,NP-Pd-TCN was used for photocatalytic hydrogen evolution under visible-light irradiation(λ>420 nm)and an excellent evolution rate of~381μmol·h^(-1)(0.02 g of the photocatalyst)was *** work aims to promote a strategy to synthesize efficient photocatalysts for hydrogen production by controllably introducing metal nanoparticles on a support and in the meantime forming chemical bonds to achieve intimate metal-support contact.

关键词： carbon nitride charge transfer dynamics photocatalysis hydrogen evolution reaction

来源：评论

学校读者我要写书评

暂无评论

Effect of loops on the mean-square displacement of Rouse-model chromatin

引用

Physical Review E 2024年第4期109卷 044502-044502页

作者： Tianyu Yuan Hao Yan Mary Lou P. Bailey Jessica F. Williams Ivan Surovtsev Megan C. King Simon G. J. Mochrie Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut 06520 USA Department of Physics Yale University New Haven Connecticut 06520 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA Department of Cell Biology Yale School of Medicine New Haven Connecticut 06520 USA Department of Molecular Cell and Developmental Biology Yale University New Haven Connecticut 06511 USA

Chromatin polymer dynamics are commonly described using the classical Rouse model. The subsequent discovery, however, of intermediate-scale chromatin organization known as topologically associating domains (TADs) in experimental Hi-C contact maps for chromosomes across the tree of life, together with the success of loop extrusion factor (LEF) model in explaining TAD formation, motivates efforts to understand the effect of loops and loop extrusion on chromatin dynamics. This paper seeks to fulfill this need by combining LEF-model simulations with extended Rouse-model polymer simulations to investigate the dynamics of chromatin with loops and dynamic loop extrusion. We show that loops significantly suppress the averaged mean-square displacement (MSD) of a gene locus, consistent with recent experiments that track fluorescently labeled chromatin loci. We also find that loops reduce the MSD's stretching exponent from the classical Rouse-model value of 1/2 to a loop-density-dependent value in the 0.45–0.40 range. Remarkably, stretching exponent values in this range have also been observed in recent experiments [Weber et al., Phys. Rev. Lett. 104, 238102 (2010); Bailey et al., Mol. Biol. Cell 34, ar78 (2023)]. We also show that the dynamics of loop extrusion itself negligibly affects chromatin mobility. By studying static “rosette” loop configurations, we also demonstrate that chromatin MSDs and stretching exponents depend on the location of the locus in question relative to the position of the loops and on the local friction environment.

关键词： Chromatin Chromosomes DNA Polymers Brownian dynamics Langevin equation Rouse model

来源：评论

学校读者我要写书评

暂无评论

Assessing traffic noise using prediction models: City of Sharjah Case Study 50

Assessing traffic noise using prediction models: City of Sha...

引用

50th International Congress and Exposition of Noise Control engineering, INTER-NOISE 2021

作者： Elmehdi, Hussein M. Ibrahem, Al-Mehdi M. Department of Applied Physics and Astronomy University of Sharjah P.O. Box 27272 Sharjah United Arab Emirates Department of Mechanical and Industrial Engineering University of Gheryan Gheryan Libya

ISBN: (纸本)9781732598652

Noise originated from traffic on inner-city roads has been recognized as a major issue that has negative effects that go beyond annoyance and adverse health effects on people living near such roads. In this paper, we report the results of employing mathematical models for assessing traffic noise levels near roads in the City of Sharjah, UAE. Our field measurements indicated high noise levels near inter-city roads including roads in residential areas. To further investigate this, measured noise levels arising from principle traffic noise parameters were re-examined using published mathematical models with the objective of validating the acoustic noise levels generated by traffic noise of mixed composition, traffic flow rate and distance from the source. The main sound levels, namely the statistical equivalent sound levels (Leq) was used in the mathematical predictive models, to calculate the day time sound levels and correlated it with in situ measurements. We have examined 12 models, reported in the literature, five of which were found to provide strong correlation and were validated for predicting noise arising from traffic. The models are recommended for calculating mixed traffic noise levels and its effects on people living near these inter-city roads. © INTER-NOISE 2021 .All right reserved.

关键词： Acoustic noise

来源：评论

学校读者我要写书评

暂无评论

Super-Mossian Dielectrics for Nanophotonics

Super-Mossian Dielectrics for Nanophotonics

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Xielin Wang Chloe F. Doiron Zhichao Li Jacob B. Khurgin Gururaj V. Naik Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX Department of Electrical and Computer Engineering Johns Hopkins University Baltimore MD Department of Electrical and Computer Engineering Rice University Houston TX

Searching for high-index dielectrics, we identify materials that break the index upper bound set by Moss’ rule. We highlight the promise of such super-Mossian materials by demonstrating nanophotonic devices made of F... 详细信息

ISBN: (纸本)9781957171258

关键词： Fourier transform infrared spectroscopy Nanophotonics Optical constants Optical materials Refractive index Whispering gallery modes

来源：评论

学校读者我要写书评

暂无评论

Low Cost Muon Telescope (LOCOMOTE) 38

Low Cost Muon Telescope (LOCOMOTE)

引用

38th International Cosmic Ray Conference, ICRC 2023

作者： Huang, Nai-Cheng Lin, Guey-Lin Lai, Kwang-Chang Huang, M.A. Liu, T.C. Institute of Physics National Yang Ming Chiao Tung University Hsinchu City Taiwan Center for General Education Chang Gung University Taoyuan City Taiwan Department of Energy Engineering National United University Taiwan Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu City Taiwan Department of applied physics National PingTung university PingTung City Taiwan Undergraduate Degree Program of Systems Engineering and Technology National Yang Ming Chiao Tung University Hsinchu City Taiwan Chung Cheng Institute of Technology National Defense University Taoyuan Taiwan Leung Center for Cosmology and Particle Astrophysics National Taiwan University Taipei Taiwan

Low Cost Muon Telescope (LOCOMOTE) is a low-cost charged particle detector. Each LOCOMOTE unit includes two pieces of BC408 (2"*2"*1") scintillators, silicon photomultipliers (SiPM), and digital logic circuits. The cost of each LOCOMOTE unit is approximately 200 US dollars and is mainly used as a teaching instrument for high school students in cosmic ray education. Each LOCOMOTE unit can be connected to the network, and data from different units can form a ground array to measure high-energy cosmic ray events. In this report, we present the performance verification of the telescope, including the measurement of cosmic muon angular flux and the feasibility of muon tomography using multiple telescopes. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Telescopes

来源：评论

学校读者我要写书评

暂无评论

Developing a Floating Robot for mechanical Control of Water Hyacinth

Developing a Floating Robot for Mechanical Control of Water ...

引用

Mobile, Intelligent, and Ubiquitous Computing Conference (MIUCC), International

作者： Mostafa E.A. Elsayed Ahmed K.A. Mohamed Mahmoud Shaaban Mohamed A. Abdelrahman Mohamed E. A. E. Ahmed Mostafa R. Rashed Mechanical Engineering Department Automation and Energy Technology Lab. Shoubra Faculty of Engineering Benha University Cairo Egypt Department of Agricultural Engineering Agricultural Power and Machinery Faculty of Agriculture Benha University Kalubia Egypt Smart Engineering Systems Center. Mechanical Engineering Program. School of Engineering and Applied Sciences Nile University Giza Egypt Mechanical Engineering Department Combustion and Energy Technology Lab. shoubra Faculty of Engineering Benha University Cairo Egypt Mechanical Engineering Department Shoubra Faculty of Engineering Benha University Cairo Egypt Mechanical Engineering Department Faculty of Engineering Modern University for Technology and Information Cairo Egypt

Water hyacinth has become widespread in freshwater bodies in several countries, leading to various issues, particularly its substantial water consumption and the resulting need to control its growth. Among the different methods of controlling water hyacinth, mechanical control stands out as the most effective and environmentally friendly approach. A proposed harvester robot has been developed, capable of efficiently cutting and collecting water hyacinth from the water's surface. The robot boasts several advantages, including its ability to operate in narrow water paths and lakes, use clean energy sources to preserve the water ecology, employ a GPS module for safety and error detection, and generate maps for evaluating work and predicting annual growth. When compared to other technologies dealing with water hyacinth, this innovative water hyacinth harvesting robot presents a significantly lower cost of 0.01 $/kg, making it an optimal solution for addressing water hyacinth problems.

关键词：

来源：评论

学校读者我要写书评

暂无评论

The Influence of Overcharging and Over-Discharging on the Capacity Degradation of Lithium-Ion Batteries

The Influence of Overcharging and Over-Discharging on the Ca...

引用

IEEE Conference on Vehicle Power and Propulsion (VPPC)

作者： Joelton Deonei Gotz Marco Antonio Simões Teixeira Fernanda Cristina Corrêa Emilson Ribeiro Viana Alceu André Badin Milton Borsato Graduate Program in Electrical and Computer Engineering Federal Technological University of Paraná (UTFPR-CT) Curitiba Brazil Graduate Program in Informatics (PPGIa) Pontifical Catholic University of Paraná (PUC-PR) Curitiba Brazil Graduate Program in Electrical Engineering Federal Technological University of Paraná (UTFPR-PG) Ponta Grossa Brazil Physics Department Graduate Program in Physics and Astronomy Federal Technological University of Paraná (UTFPR-CT) Curitiba Brazil Graduate Program in Mechanical Engineering Federal Technological University of Paraná (UTFPR-CT) Curitiba Brazil

ISBN: (数字)9798331541606

ISBN: (纸本)9798331541613

Lithium-ion batteries (LIB) are the best technology for supplying and storing energy for electric mobility systems. Despite that, this technology is sensitive to abuses that can compromise its lifetime and cause fire and explosion risks. In this context, if LIB is not correctly controlled, some abuses, such as overcharging (OC) and over-discharging (OD), can be observed and provoke a loss of capacity. Therefore, this work presented the application of several experiments in cells, of the NMC type, under OC and the combination of OC and OD. The results indicated that cells charged until 4.4 and 4.5 V and discharged until 3.0 V do not lose capacity for twenty-five cycles, but more cycles should be done to understand the impact over time. On the other side, the cell charged until 4.6 and 4.8 V had its security protection romped in the fourth charging cycle, and the cell charged until 5.0 V had its safety compromised in the first charging cycle. Conversely, cells with a combination of OC and OD were more compromised. In this context, while a cell is submitted only with OC and does not lose capacity, a cell under OC and then under OD had its protection romped in the third charging cycle. Cells under 4.6 V and 4.8 V lost capacity during the second charging cycle. In conclusion, OC provokes a high level of degradation in the cell, but the combination of OC and OD causes even more degradation.

关键词： Degradation Lithium-ion batteries Battery management systems Propulsion Security Reliability Protection Stress Monitoring Predictive maintenance

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：